Gets or sets the List GUID.
Assembly: Microsoft.SharePoint.Publishing (in Microsoft.SharePoint.Publishing.dll)
The WebUrl property determines the ContentByQueryWebPart object's mode is determined by the WebUrl, , and ListName properties.
If the WebUrl, ListGuid, and ListName properties are set, the mode is List.
If the WebUrl is set and ListGuid and ListName are empty, the mode is Web.
If WebUrl, ListGuid and ListName are empty, the mode is Site Collection.
If both ListGuid and ListName properties are set, ListGuid takes precedence.